Self-testing using only marginal information

TL;DR

This paper extends the concept of self-testing in quantum information from fully characterized measurements to a device-independent framework, demonstrating that certain two-party correlations can uniquely identify pure three-qubit states.

Contribution

It introduces sets of two-party correlations capable of self-testing pure three-qubit states within a device-independent setting.

Findings

Sets of two-party correlations can uniquely determine certain three-qubit states.

The approach generalizes self-testing beyond tomographic information.

Results enable device-independent verification of multipartite quantum states.

Abstract

The partial states of a multipartite quantum state may carry a lot of information: in some cases, they determine the global state uniquely. This result is known for tomographic information, that is for fully characterized measurements. We extend it to the device-independent framework by exhibiting sets of two-party correlations that self-test pure three-qubit states.